Obesity Is a Risk Factor for Severe COVID-19 Infection: Multiple Potential Mechanisms

Abstract

HomeCirculationVol. 142, No. 1Obesity Is a Risk Factor for Severe COVID-19 Infection Free AccessArticle CommentaryPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessArticle CommentaryPDF/EPUBObesity Is a Risk Factor for Severe COVID-19 InfectionMultiple Potential Mechanisms Naveed Sattar, Iain B. McInnes and John J.V. McMurray Naveed SattarNaveed Sattar Naveed Sattar, MD, Institute of Cardiovascular and Medical Sciences, British Heart Foundation Glasgow Cardiovascular Research Centre, University of Glasgow, 126 University Place, Glasgow G12 8TA, United Kingdom. Email E-mail Address: [email protected] https://orcid.org/0000-0002-1604-2593 Institute of Cardiovascular and Medical Sciences (N.S., J.J.V.M.), University of Glasgow, United Kingdom. , Iain B. McInnesIain B. McInnes Institute of Infection, Immunity and Inflammation (I.B.M.), University of Glasgow, United Kingdom. and John J.V. McMurrayJohn J.V. McMurray Institute of Cardiovascular and Medical Sciences (N.S., J.J.V.M.), University of Glasgow, United Kingdom. Originally published22 Apr 2020https://doi.org/10.1161/CIRCULATIONAHA.120.047659Circulation. 2020;142:4–6Other version(s) of this articleYou are viewing the most recent version of this article. Previous versions: April 22, 2020: Ahead of Print The coronavirus disease 2019 (COVID-19) pandemic has led to worldwide research efforts to identify people at greatest risk of developing critical illness and dying. Initial data pointed toward older individuals being particularly vulnerable, as well as those with diabetes mellitus or cardiovascular (including hypertension), respiratory, or kidney disease. These problems are often concentrated in certain racial groups (eg, African Americans and Asians), which also appear to be more prone to worse COVID-19 outcomes.1 Increasing numbers of reports have linked obesity to more severe COVID-19 illness and death.1–3 In a French study, the risk for invasive mechanical ventilation in patients with COVID-19 infection admitted to the intensive treatment unit was more than 7-fold higher for those with body mass index (BMI) >35 compared with BMI <25 kg/m2.2 Among individuals with COVID-19 who were <60 years of age in New York City, those with a BMI between 30 to 34 kg/m2 and >35 kg/m2 were 1.8 times and 3.6 times more likely to be admitted to critical care, respectively, than individuals with a BMI <30 kg/m2.3We suggest obesity or excess ectopic fat deposition may be a unifying risk factor for severe COVID-19 infection, reducing protective cardiorespiratory reserve as well as potentiating the immune dysregulation that appears, at least in part, to mediate the progression to critical illness and organ failure in a proportion of patients with COVID-19 (Figure). Whether obesity is an independent risk factor for susceptibility to infection requires further research.Download figureDownload PowerPointFigure. Pathways potentially linking obesity or excess ectopic fat to more severe coronavirus disease 2019 (COVID-19) illness. There are multiple pathways by which obesity (or excess ectopic fat) may increase the effect of COVID-19 infection. These include underlying impairments in cardiovascular, respiratory, metabolic, and thrombotic pathways in relation to obesity, all of which reduce reserve and ability to cope with COVID-19 infection and the secondary immune reaction to it. At the same time, there are several reasons why obese individuals may have amplified or dysregulated immune response, linked both to greater viral exposure, as well as the possibility that excess adipose tissue potentiates the immune response. BP indicates blood pressure; COVID-19, coronavirus disease 2019; CV, cardiovascular; FEV1, forced expiratory volume; FVC, forced vital capacity; and SES, socioeconomic status.From a cardiovascular perspective, trial and genetic evidence conclusively show that obesity (and excess fat mass) are causally related to hypertension, diabetes mellitus, coronary heart disease, stroke, atrial fibrillation, renal disease, and heart failure. Obesity potentiates multiple cardiovascular risk factors, the premature development of cardiovascular disease, and adverse cardiorenal outcomes. There is also a metabolic concern. In individuals with diabetes mellitus, or at high risk of diabetes mellitus, obesity and excess ectopic fat lead to impairment of insulin resistance and reduced β-cell function. Both the latter limit ability to evoke an appropriate metabolic response on immunologic challenge, leading some patients with diabetes mellitus to require substantial amounts of insulin during severe infections. Overall, the integrated regulation of metabolism required for the complex cellular interactions, and for effective host defense, is lost, leading to functional immunologic deficit. COVID-19 may also directly disrupt pancreatic β-cell function through an intera